Method and apparatus for providing piggybacked positive acknowledgement/negative acknowledgement field indicator and a polling indicator

ABSTRACT

A method and apparatus of providing a piggybacked positive acknowledgement/negative acknowledgement (ACK/NACK) (PAN) field indicator (PANI) and a polling indicator are disclosed. A combined field of a PANI bit, a relative reserved block period (RRBP) bit and an EGPRS supplementary polling (ES/P) field may indicate a polling scheme and a presence of a PAN field. Alternatively, the presence of the PAN field in the data block may be indicated by using a specific training sequence. Alternatively, a forward error correction (FEC) coding may be performed on the data block including the header, and the presence of the PAN field may be indicated by scrambling the encoded bits corresponding the header with a specific scrambling sequence. Alternatively, a header check sequence (HCS) may be generated and the presence of the PAN field is indicated by mixing a predetermined sequence with the HCS.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.12/116,291, filed May 7, 2008, which claims the benefit of U.S.Provisional Application No. 60/916,691 filed May 8, 2007, which isincorporated by reference as if fully set forth.

FIELD OF INVENTION

This application is related to wireless communications.

BACKGROUND

Latency reduction is one of the considerations in a GSM/EDGE radioaccess network (GERAN). Two techniques have been proposed for thelatency reduction: reduced transmission time interval (RTTI) and fastacknowledgement/non-acknowledgement (ACK/NACK) reporting (FANR).

Under current GERAN protocols, the network may obtain feedback data,(i.e., ACK/NACK of downlink data packets), from the mobile stationthrough polling. The polling is indicated by an evolved general packetradio service (EGPRS) supplementary polling (ES/P) field. Two (2) ES/Pbits indicate whether a relative reserved block period (RRBP) field isvalid or not and what fields the next uplink control block shallcontain.

FIGS. 1-3 show conventional EGPRS downlink radio link control/mediumaccess control (RLC/MAC) header types 1, 2, and 3, respectively. Boththe ES/P field and the RRBP field are present in all three RLC/MACheader types. Table 1 shows the meaning of the conventional 2-bit ES/Pfield.

TABLE 1 bits 5 4 ES/P 0 0 RRBP field is not valid (no Polling) 0 1 RRBPfield is valid - Extended Ack/Nack bitmap type FPB 1 0 RRBP field isvalid - Piggy-backed Ack/Nack bitmap type FPB 1 1 RRBP field is valid -Extended Ack/Nack bitmap type NPB, measurement report included

Conventionally, an ACK/NACK report is sent in an explicit message, alsoreferred to as an RLC/MAC control block. The ACK/NACK report isaddressed to a particular radio resource, called a Temporary Block Flow(TBF). A TBF is a temporal connection between a mobile station and anetwork to support a uni-directional transfer of data. A TBF istemporary and is maintained only for the duration of the data transfer.

It has been proposed that the ACK/NACK feedback for a certain TBF be“piggybacked” on an RLC/MAC data block that may be addressed to anotherTBF. The field that carries this ACK/NACK feedback is referred to as“piggybacked ACK/NACK (PAN) field”. The presence or absence of the PANfield in the RLC/MAC data block is indicated by a PAN indicator (PANI).

In order to send the PANI, an extra bit may be included in a downlinkdata packet header as shown in FIGS. 1-3. However, currently there is noavailable space in the downlink data packet header. It has been proposedto split the conventional 2-bit RRBP field such that one bit is used forthe RRBP field and the other bit is used for the PANI. Tables 2 and 3show the meaning of the 1-bit RRBP field and 1-bit PANI field.

TABLE 2 Bit Full-rate PDCH uplink block with TDMA frame number 0 (N + 8or N + 9) mod 2715648 1 (N + 13) mod 2715648

TABLE 3 bit PANI 0 A PAN field is not included 1 A PAN field is included

In accordance with this proposal, the header size remains the same.However, there is redundancy in bit combinations. If the ES/P bits are“00”, (i.e., when there is no polling request), the combinations of theRRBP bit and the PANI bit include wastage of three (3) combinations.Therefore, it would be desirable to provide a scheme for more efficientsignaling of a PANI, an RRBP, and a polling indicator.

SUMMARY

A method and apparatus of providing a PANI and a polling indicator aredisclosed. A combined field of a PANI bit, an RRBP bit, and an ES/Pfield may indicate a polling scheme and a presence of a PAN field.Alternatively, the presence of the PAN field in the data block may beindicated by using a specific training sequence. Alternatively, aforward error correction (FEC) coding may be performed on the data blockincluding the header, and the presence of the PAN field may be indicatedby scrambling the encoded bits corresponding the header with a specificscrambling sequence. Alternatively, a header check sequence (HCS) may begenerated and the presence of the PAN field is indicated by mixing apredetermined sequence with the HCS. Block sequence number 2 (BSN2) bitsmay be used to indicate the existence of a PAN field.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIGS. 1-3 show conventional EGPRS downlink RLC/MAC header types 1, 2,and 3, respectively;

FIG. 4 is a block diagram of a base station in accordance with the thirdembodiment;

FIG. 5 is a block diagram of a WTRU in accordance with the thirdembodiment;

FIG. 6 is a block diagram of a base station in accordance with thefourth embodiment; and

FIG. 7 is a block diagram of a WTRU in accordance with the fourthembodiment.

DETAILED DESCRIPTION

When referred to hereafter, the terminology “wireless transmit/receiveunit (WTRU)” includes but is not limited to a user equipment (UE), amobile station, a fixed or mobile subscriber unit, a pager, a cellulartelephone, a personal digital assistant (PDA), a computer, or any othertype of user device capable of operating in a wireless environment. Whenreferred to hereafter, the terminology “base station” includes but isnot limited to a Node-B, a site controller, an access point (AP), or anyother type of interfacing device capable of operating in a wirelessenvironment.

In accordance with a first embodiment, a 1-bit PANI field, a 1-bit RRBPfield, and a 2-bit ES/P field in an RLC/MAC header are combined togetherto indicate a polling scheme and an existence of a PAN field in the datablock. The bit combinations of the PANI field, the RRBP field and theES/P field do not have any redundancy. Example PANI, RRBP and ES/P bitcombinations and their meaning are shown in Table 4.

In Table 4, the first bit, read from left, is a PANI field, the secondbit is an RRBP field, and the third and fourth bits are an ES/P field.When the first bit, (i.e., the PANI field), is set to ‘1’, it indicatesthat a PAN field is included in the data block, and if the first bit isset to ‘0’, it indicates that a PAN field is not included in the datablock. It should be noted that the bit combinations in Table 4 areprovided as an example, not as a limitation, and any other combinationmay be used and any other meaning may be associated with the bitcombinations.

TABLE 4 PANI + RRBP + ES/P Meaning 0 0 0 0 No Polling; No PAN 0 1 0 0Polling (FPB bitmap; N + M); No PAN 1 0 0 0 Polling (FPB bitmap asUL-PAN; N + M); PAN 1 1 0 0 No Polling; PAN 0 0 0 1 Polling (FPB bitmap;N + 8 or N + 9); No PAN 0 1 0 1 Polling (FPB bitmap; N + 13); No PAN 1 00 1 Polling (FPB bitmap; N + 8 or N + 9); PAN 1 1 0 1 Polling (FPBbitmap; N + 13); PAN 0 0 1 0 Polling (FPB bitmap as UL-PAN; N + 8 or N +9); No PAN 0 1 1 0 Polling (FPB bitmap as UL-PAN; N + 13); No PAN 1 0 10 Polling (FPB bitmap as UL-PAN; N + 8 or N + 9); PAN 1 1 1 0 Polling(FPB bitmap as UL-PAN; N + 13); PAN 0 0 1 1 Polling (CQR - NPB bitmap;N + 8 or N + 9); No PAN 0 1 1 1 Polling (CQR - NPB bitmap; N + 13); NoPAN 1 0 1 1 Polling (CQR - NPB bitmap; N + 8 or N + 9); PAN 1 1 1 1Polling (CQR - NPB bitmap; N + 13); PAN

For example, the bit combinations 0100 and 1000 may be used to specifyadditional polling schemes, (e.g., those eliminated in reducing theconventional RRBP bits from 2 to 1), or to demand reporting of channelquality report (CQR) or next partial bitmap (NPB) when there is notenough space to send both. The parameter M may be chosen suitably.

In accordance with a second embodiment, a training sequence is used toindicate the presence of the PAN field in the RLC/MAC data block. Underthe current GERAN specification, one of eight (8) training sequences isused for communication between a WTRU and a network in a cell. Inaccordance with the second embodiment, eight (8) training sequencegroups are defined with each group having two (2) training sequences.One training sequence is used in a cell for all communications betweenthe WTRU and the network and the presence of a PAN field in the RLC/MACdata block is indicated by using the other training sequence in thattraining sequence group.

In accordance with a third embodiment, a scrambling code is used toindicate the presence of the PAN field in the RLC/MAC data block. FIG. 4is a block diagram of a base station 400 in accordance with the thirdembodiment. The base station 400 includes a data block processing entity402, an encoder 404, a scrambler 406, and a transceiver 408. The datablock processing entity 402 generates a data block including a header.The header includes the ES/P field and the RRBP field. The encoder 404performs an FEC coding on the data block including the header. If thedata block does not include a PAN field, the data block is transmittedby the transceiver 408 as in the prior art. If the data block includes aPAN field, the scrambler 406 scrambles the encoded bits corresponding tothe header with a scrambling sequence and the data block including thescrambled bits are transmitted by the transceiver 408.

For scrambling, the encoded bits are modulo-2 added to a pre-specifiedscrambling sequence. The length of the scrambling sequence may be sameto that of the encoded bits corresponding to the header. The scramblingsequence is unique and known to both the base station and the WTRU. Thescrambling code may be generated in a number of ways, or selected inaccordance with criterion that the distance between the scrambling codeand the all “zero” sequence is maximized.

FIG. 5 is a block diagram of a WTRU 500 in accordance with the thirdembodiment. The WTRU 500 includes a transceiver 502, a decoder 504, adescrambler 506, and a controller 508. The transceiver 502 receives abit sequence of a data block from the base station 400. The decoder 504performs FEC decoding on the received bit sequence as in the prior art.If the data block does not include a PAN field and therefore the bitscorresponding to the header was not scrambled at the base station 400,the decoder 504 may succeed in decoding. However, if the data blockincludes a PAN field and therefore the bits corresponding to the headerwas scrambled at the base station 400, the received bit sequence will berejected due to having too many bit errors. If the received bit sequenceis rejected, the received bits corresponding to the header aredescrambled, (i.e., modulo-2 added with the scrambling sequence), by thedescrambler 506. The received bit sequence with the descrambled headerportion of the bit sequence is then decoded again by the decoder 504. Ifthe second FEC decoding is successful, the controller 508 detects that aPAN field is included in the data block.

In accordance with a fourth embodiment, a modified HCS is used toindicate the presence of the PAN field. A radio block for data transferincludes one RLC/MAC header, an HCS, one or more RLC data block(s), anda block check sequence (BCS). The data block may include a PAN field andan optional PAC check sequence (PCS). The HCS is used for errordetection of the RLC/MAC header. The HCS may be eight bits long.

FIG. 6 is a block diagram of a base station 600 in accordance with thefourth embodiment. The base station 600 includes a data block processingentity 602, a HCS encoder 604, a modulo-2 adder 606, and a transceiver608. The data block processing unit 602 generates a data block includinga header. The header includes an ES/P field and an RRBP field. The HCSencoder 604 generates an HCS. If the radio block does not include a PANfield, the radio block is transmitted by the transceiver 608 as in theprior art. If the radio block includes a PAN field, the modulo-2 adder606 adds a predetermined sequence to the HCS, and the radio block withthe modified HCS is transmitted by the transceiver 608. For example, asequence 11111111 may be used as the predetermined sequence. In thiscase, the HCS bits are inverted.

FIG. 7 is a block diagram of a WTRU 700 in accordance with the fourthembodiment. The WTRU 700 includes a transceiver 702, an HCS decoder 704,a modulo-2 adder 706, and a controller 708. The transceiver 702 receivesa data block from the base station 600. The HCS decoder 704 performingHCS decoding with the received header of the data block and the receivedHCS. If the header is received error free, (i.e., the HCS check passes),the controller 708 may assume that no PAN is present in the RLC/MAC datablock. If the HCS check fails, the received header is modulo-2 addedwith the predetermined sequence by the modulo-2 adder 706, and HCS checkis performed again. If the second HSC check passes, the controller 708may assume that the header is correct and the PAN field is included inthe RLC/MAC data block.

In accordance with a fifth embodiment, the existence of a PAN field maybe signaled using block sequence numbers (BSNs). Currently, the headerincludes an 11 bit BSN1 and a 10 bit BSN2. Once the BSN1 is specified,BSN2 is forced to be within a certain vicinity of BSN1. The vicinity isspecified by a window size (WS). Conventionally, a WS of 10 bits isadequate. In accordance with the fifth embodiment, the current WS ishalved so that only 9 bits are needed to signal BSN2. The unused tenthBSN2 bit in the header may be used to indicate a PANI.

Although features and elements are described above in particularcombinations, each feature or element can be used alone without theother features and elements or in various combinations with or withoutother features and elements. The methods or flow charts provided hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable storage medium for execution by ageneral purpose computer or a processor. Examples of computer-readablestorage mediums include a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs).

Suitable processors include, by way of example, a general purposeprocessor, a special purpose processor, a conventional processor, adigital signal processor (DSP), a plurality of microprocessors, one ormore microprocessors in association with a DSP core, a controller, amicrocontroller, Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs) circuits, any other type of integratedcircuit (IC), and/or a state machine.

A processor in association with software may be used to implement aradio frequency transceiver for use in a wireless transmit receive unit(WTRU), user equipment (UE), terminal, base station, radio networkcontroller (RNC), or any host computer. The WTRU may be used inconjunction with modules, implemented in hardware and/or software, suchas a camera, a video camera module, a videophone, a speakerphone, avibration device, a speaker, a microphone, a television transceiver, ahands free headset, a keyboard, a Bluetooth® module, a frequencymodulated (FM) radio unit, a liquid crystal display (LCD) display unit,an organic light-emitting diode (OLED) display unit, a digital musicplayer, a media player, a video game player module, an Internet browser,and/or any wireless local area network (WLAN) or Ultra Wide Band (UWB)module.

1. A method for reporting apositive-acknowledgement/negative-acknowledgement (ACK/NACK) in responseto a received data block, the method comprising: receiving a data blockincluding a header, wherein the header includes a sequence of bits forindicating both an ACK/NACK polling scheme and a presence or absence ofa piggybacked ACK/NACK (PAN) field in the data block, and each of aplurality of bit combinations of the sequence indicates a differentcombination of an the ACK/NACK polling scheme and the presence orabsence of the PAN field; processing the PAN field on a condition thatthe sequence indicates the presence of the PAN field in the data block;and sending feedback based on the ACK/NACK polling scheme indicated bythe sequence.
 2. The method of claim 1, wherein the sequence includes afirst field for indicating the presence or absence of the PAN field. 3.The method of claim 2, wherein the sequence includes a second field forindicating the ACK/NACK polling scheme.
 4. The method of claim 1,wherein the PAN field of the data block is addressed to a first wirelesstransmit/receive unit (WTRU) and a payload of the data block isaddressed to a second WTRU.
 5. The method of claim 1, wherein the datablock is received via a GSM/EDGE radio access network (GERAN).
 6. Awireless transmit/receive unit (WTRU) for reporting apositive-acknowledgement/negative-acknowledgement (ACK/NACK) in responseto a received data block, the WTRU comprising: a transceiver configuredto receive a data block including a header and a payload, wherein theheader includes a sequence of bits for indicating both an ACK/NACKpolling scheme and a presence or absence of a piggybacked ACK/NACK (PAN)field in the data block, and each of a plurality of bit combinations ofthe sequence indicates a different combination of an the ACK/NACKpolling scheme and the presence or absence of the PAN field; and acontroller configured to process the PAN field on a condition that thesequence indicates the presence of the PAN field in the data block, andsend feedback based on the ACK/NACK polling scheme indicated by thesequence.
 7. The WTRU of claim 6, wherein the sequence includes a firstfield for indicating the presence or absence of the PAN field.
 8. TheWTRU of claim 7, wherein the sequence includes a second field forindicating the ACK/NACK polling scheme.
 9. The WTRU of claim 6, whereinthe PAN field of the data block is addressed to a first wirelesstransmit/receive unit (WTRU) and a payload of the data block isaddressed to a second WTRU.
 10. The WTRU of claim 6, wherein the datablock is received via a GSM/EDGE radio access network (GERAN).
 11. Amethod for requesting apositive-acknowledgement/negative-acknowledgement (ACK/NACK) for a datablock, the method comprising: generating a data block including aheader, wherein the header includes a sequence of bits for indicatingboth an ACK/NACK polling scheme and a presence or absence of apiggybacked ACK/NACK (PAN) field in the data block, and each of aplurality of bit combinations of the sequence indicates a differentcombination of an the ACK/NACK polling scheme and the presence orabsence of the PAN field; and transmitting the data block.
 12. Themethod of claim 11, wherein the sequence includes a first field forindicating the presence or absence of the PAN field.
 13. The method ofclaim 12, wherein the sequence includes a second field for indicatingthe ACK/NACK polling scheme.
 14. The method of claim 11, wherein the PANfield of the data block is addressed to a first wirelesstransmit/receive unit (WTRU) and a payload of the data block isaddressed to a second WTRU.
 15. The method of claim 11, wherein the datablock is transmitted via a GSM/EDGE radio access network (GERAN).
 16. Anapparatus for receiving apositive-acknowledgement/negative-acknowledgement (ACK/NACK) for a datablock, the apparatus comprising: a controller configured to generate adata block including a header and a payload, wherein the header includesa sequence of bits for indicating both an ACK/NACK polling scheme and apresence or absence of a piggybacked ACK/NACK (PAN) field in the datablock, and each of a plurality of bit combinations of the sequenceindicates a different combination of an the ACK/NACK polling scheme andthe presence or absence of the PAN field; and a transmitter configuredto transmit the data block.
 17. The apparatus of claim 16, wherein thesequence includes a first field for indicating the presence or absenceof the PAN field.
 18. The apparatus of claim 17, wherein the sequenceincludes a second field for indicating the ACK/NACK polling scheme. 19.The apparatus of claim 16, wherein the PAN field of the data block isaddressed to a first wireless transmit/receive unit (WTRU) and a payloadof the data block is addressed to a second WTRU.
 20. The apparatus ofclaim 16, wherein the data block is transmitted via a GSM/EDGE radioaccess network (GERAN).